In conventional aircraft it is commonplace to use panels made up of a skin and of stiffeners fixed to the skin in order to give it the necessary stiffness. The skin is, in general, several millimeters thick. As for the stiffeners, these are, for example, T-section or I-section stiffeners, each having a flange (sole) by means of which they are assembled with the skin, generally by riveting.
These stiffeners have a web of a height sufficient to allow the stiffeners to be assembled with one another and with the surrounding structure by means of fishplates fixed to the webs of the stiffeners.
FIG. 1 illustrates one example of such a conventional panel 10, in this instance a panel extending over the windscreen 12 of an airplane and connected to the upper surround 14 of the windscreen and to a circumferential fuselage frame 15. Such a panel is sometimes referred to as a “windscreen visor.”
FIG. 1 shows the skin 16 of the panel 10 and stiffeners 18 thereof, which are sometimes referred to as “uprights.” These stiffeners are connected to one another, to the surround 14 or to the circumferential frame 15 by means of fishplates.
FIG. 2 thus illustrates the connection between two of the stiffeners 18A and 18B of the panel 10 by means of fishplates 20.
However, recent developments in aircraft construction tend to promote the use of self-stiffened panels, which means to say panels made up of a skin and of a stiffening structure incorporated into the skin.
The use of self-stiffened panels, in general, makes it possible to reduce the number of components and the number of assembly operations, to reduce the number of fixing elements and therefore the mass of the panel, and to improve the stiffness of the panel.
However, the relatively short height of the ribs that make up the stiffening structure of such a panel and the relatively high density of these ribs do not allow the stiffening structure to be assembled with the surrounding structure using fishplates.